/**
  * @param string|Workflow|WorkflowItem|WorkflowDefinition $workflowIdentifier
  */
 public function activateWorkflow($workflowIdentifier)
 {
     if ($workflowIdentifier instanceof WorkflowDefinition) {
         $entityClass = $workflowIdentifier->getRelatedEntity();
         $workflowName = $workflowIdentifier->getName();
     } else {
         $workflow = $this->getWorkflow($workflowIdentifier);
         $entityClass = $workflow->getDefinition()->getRelatedEntity();
         $workflowName = $workflow->getName();
     }
     $this->setActiveWorkflow($entityClass, $workflowName);
 }